Denon AVR-788 Receiver shuts off when cold when volume is turned up even with no input or speakers
Ғылым және технология
A Denon AVR-788 AV Receiver with a weird symptom, Even with no inputs and no speakers connected if the volume is raised when the unit is cold it will shut down. If you keep the volume low for the first few minutes the unit will work perfectly. I found a bunch of (20+) bad capacitors. Unit is working great now.
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00:00 Intro
00:28 Look at the current draw
02:06 Look at the surr-R bias
04:04 49khz oscillation on surr-R ch
04:46 DSP and power amp schematic
06:06 Input board layout
06:47 Possible bad capacitors?
07:38 Cooling the capacitors
08:22 Separating main amp from DSP tests
09:43 ESR caps on DSP board
12:23 Bad SMD caps on HDMI board?
13:36 Twisting off old capacitors
14:08 Installing new capacitors
15:18 Tests after capacitor replacement
16:20 Audio tests
17:18 Closing words
Пікірлер: 29
Nice repair a real head scratcher on this one.
My Denon a/v receiver was doing the shut-down and I realized that Zone2 (unused/no speakers connected) was set to a high volume level. Problem disappeared when I turned Zone2 off. I don't think it was faulty, just a really crappy design. With speakers connected, Zone2 worked totally fine.
This was really interesting phenomenon and nice repair! Thank you.
I really really love your repair..
Great repair job! Great video! Thank you.
Love your projects.
Great troubleshooting skills!
Mr NorCal I appreciate your repair.. I would like to be like you ..
Great Channel!
amazing video.
You are really good dude. :)
I understand how tough this avr repair works
Love it! WOW, that is almost ready for a complete recapping. SMD caps.........SMH. Worst thing ever invented for electronics.
I have a Denon AVR-1908, it's pretty simular to this one. I'm facing a similar problem, I need to set the volume way higher than expected to just hear a high pitch noise and barely hear the sound that I'm playing. When I set the volume to 10dB, it starts to smoke from the amp board. Watching your video I will try to listen the sound directly from the DSP board, to try to identify if the problem is coming from that.
Would really wanted to know why it was the hdmi board, sure there are inputs and outputs for hdmi but I don't understand why the volume would affect hdmi functionality where you only get audio and video signals.
Cap rot strikes again but a good find. I have always wondered, how to keep amplifiers going. Any advice. Perhaps that would be a good video. Myself I leave them on all the time, amps that is, never put them in a rack or put anything on top. If they are off, not having anything blasting out when the relays kick in. In other ideas or do I have it all wrong?
@norcal715
2 жыл бұрын
The thermal cycling can lead to bad solder connections. Setting the volume at minimum upon power up is a good idea too. The cooler they run the longer they will last also.
How to identify which IC control the volume on denon avr? Please reply
Great job my demon is doing the exact thing looks like I it to get to soldering. Or can I send it to you
How can you help me please I have an amplifier it works normally but as soon as I increase the volume it automatically turns off and sometimes even blows the fuse 
How much would one of these repairs cost?
do you sell mcu denon avr 1311, toshiba T5CN5
Nice fault finding.
I have a reciever with the exact same issue, I don't want it you can have it if you want lol
@norcal715
17 күн бұрын
Where are you located, I am in Northern California (Chico)
@jeremiemorotti
17 күн бұрын
Up in Canada, I ended up taking it to e-recycle a few days ago tho so it's gone to the wind now lol
Hi
Fastest soldering in the world
disappointing number of dead caps - I'm guessing these are simply crap quality china specials thanks to cost cutting. This thing cant even be that old since it has HDMI